Centrifugal casting machine



July 14, '1936-l i J. H'LEDEBOER 2,047,588

CENTRIFUGAL CASTING MACHINE' File'd Feb. 17, 1934 2 SheelS-Sheetc 1 July'14, 1936. L H LEDEBOER 2,047,588

lMNTMFUGAL CASTING MACHINE Filed Feb. 17', 1934 2 Sheets-Sheet 2 Patented July 14, 1936 PATENT OFFICE CENTRIFUGAL CASTING MACHINE Jeremas H. Ledeboer, Beverwijk, Netherlands,

assignor to Koninklijke Nederlandsche Hoogovens en Staall'abrieken Netherlands, a company of theNetherlands Application February 17, 1934, Serial No. 711,775 In the Netherlands February 21, 1933 6 claims. (ci. zz-ss) f This invention relates to certain new and use- -fui improvements in centrifugal casting machines and more particularly to machines of the type for producing relatively long cylindrical castings in refractory lined molds or asks. Machines of this type as hitherto used are as a rule so arranged that the mold is supported intermediate its ends in two spaced places by supporting rollers and is adapted through a magnetic clutch, to be driven at one end only or to be driven by the supporting rollers themselves. Driving the mold at one end only has the disadvantagethat it'is hardly possible to ensure correct alignment of the ldriving shaft and the axis of the mold supported by the said rollers, which mold may have various diameters. In

this respect, driving the mold through the sup- 4 porting rollers has marked advantages, although it is' a drawback of last said construction that 2o the rollers and the races thereforeare liable to unequal wear and tear and ar dimcult to clean, which interferes with the correct rotation of the mold and. consequently, with the quality of the casting. 2s The present invention has for its objectto obviate said disadvantages. With this object in view, the mold is not supported intermediate its ends by rollers, but exclusively at both ends, on the one side by a drive shaft rigidly supw ported in'twoor'morebearings so as to occupy an invariable position, at the other end by a revoluble head through which the molten metal can' be' poured into the mold, said head being supported by a pedestal through a ball bearing 8d or the like encircling the mould engaging surface or surfaces of the revoluble head and 'located substantially in the same vertical plane at right angles to the axis of rotation.

In this manner the mold is supported at both 40 ends so that no vibratory motion can be set up therein during the casting and, as a consequence the -solidication of the cast metal, notwithlstanding the considerable centrifugal forces re-, '15 sulting, for instance, from unsymmetrical lining thereof, after the casting operation or during adapted for axial displacementto enable the casting of pipe or the like of various lengths, when the driven head and the pouring trough or spout with associate parts may remain stationary. 5 With a driven or casting head arranged as stated above, the ball bearing provided thereon is not too much exposed to the radiant heat of the molten metal in the ladle, the spout and the mold, especially not if the mold itself, or a 10 member forming in effect a continuation thereof,- is arranged to project from the driven head and the fast head stock is fitted with a shield or diaphragm for checking the radiant heat of the molten metal and of the ladle. Such a 15 diaphragm may also be tted to the driving head or to the core for the bell end of the pipe, or the said core may be made sofas to completely close the-mold at said end.

To also reduce the rate of heat transference 20.

by conduction from the mold to the ball bearing, the surface of the driven head, designed to engage frictionally with a corresponding surface lugs through which the heads engage the mold may be of volute or impeller form, or fins of said y form may be provided intermediate the lugs, so that during rotation of the mold and after the casting 4air is caused to flow through the gap or gaps between the mold and the heads. Under these conditions, said head cannot be. excess- `ive1y heated by the hot mold. On the side of the driving head the current oi' cooling fluid may be forced into and through the mold so as to influence the rate of cooling and consequently the qualityfof the casting. In order to produce 4.0 f

a very strong current of cooling fluid for the last said purpose, the driving head may be provided also on the other side with apertures and impeller fins, or said apertures may be enclosed byj a stationary case connected to a compressed air or other gas supply pipe.

In order that a fresh mold may be readily in serted, and that minor inaccuracies in the assemblage of the various parts of the machine may be compensated for, the bearing of the driven head, if fitted ina movable head stock, may be arranged for oscillation about horizontal trunnions in a lyoke ada ted for swinging motion about a fixed axis in p rallel relation with Said trunnions andv engaged by\`hydraulic or 55.

pneumatic means whereby the driven head may be forced into frictional engagement with, the

mold.

With this construction and when the mold is heated so as to expand, the driven head is adapted to yield against a constant pressure, during which movement the said head remains parallel with itself at a substantially constant level, and consequently in correct engagement with the mold.

With a view to possible damage and in order that pipe or the like of different diameters may be cast, the ball or like bearing (oi` the Micheli bearing that may be used if the pipe has a large diameter and must be rotated 'at a very high speed), as well as the parts which directly engage the mold may be arranged to be readily exchangeable. 'I'he same applies to the driving head.

The annexed drawings serve to further illustrate the invention.

Fig. 1 is a more or less diagrammatic side view of a centrifugal casting machine in which the driven head is provided in a fast head stock and the driving head in a sliding head stock or carriage.

Fig. 2 is a cross-sectional view along the line II-II in Fig. 1, on an enlarged scale.

Figs. 3, 4, and 5 are a side elevational view partly in section, a front view, and a sectional view along the line V--Vv in Fig. 3, respectively, of a driven head provided in a movable head stock.

Figs. 6 and 7 illustrate axial sectional views of driving heads of different construction.

The mold l (Fig. 1) is provided with reinforcing rings 2, and formed on either end with a taper outer surface adapted to engage frictionally with corresponding taper inner surfaces of the heads 3 and 4 of the casting machine.

The head 3 is secured to the free end of a shaft 5 journaled in bearings 6 and coupled through a magnetic clutch l with an electromotor il. The bearings and the motor are mounted on a slide 9 supported by a second slide I0, which in turn is supported by a bed plate II secured to the foundation (Fig. 2).

The slides 9 and I0 are interconnected by a double acting hydraulic cylinder I2, which is secured to the slide I0, and through a hydraulic plunger I3, the rod I4 of which engages the slide 9. When the slide I0 is locked in position, the slide 9 is adapted under the action of hydraulic pressure to be moved forward, when the mold I is to be engaged between the heads 43 and 4. During the casting operation and the consequential heat expansion of the mold, the slide 9 is adapted to yield against the action of the hydraulic pressure on the plunger I3, while continuing to exert the required axial pressure on the mold I.

Mounted in the slide I0 is a transverse shaft I5 provided outside the slide with a ratchet handle I6, and inside the slide with two pinions I'I meshing with racks I8 on the bed plate I I. By means of this arrangement the slide Ill is adapted, by manual force, to be axially displaced with respect to the bed II and to be moved into the required position responsive to the length of the mold. The slide I0 is further provided with strips I9 engaged by nuts on screw bolts 20, by means of whichthe slide I can be locked in position in such a manner as to allow the slide 3 to move to and fro. I1 Ihe driven head (Fig. 1) consists of an annular member 4 which is revoluble in a stationary sleeve 2l supported by a pedestal 22. The pouring trough or runner 23, which extends through said head, is illustrated in dash and dot lines, as well as the ladle 24 in its raised position. 5

In accordance with Figs. 3-5, the driven head 4 is fitted in a non-revoluble sleeve or annulus 25 provided on the rear side with a diaphragm 26 and on either lateral side with a trunnion 21 engaging a yoke 28 hinged as at 29 to brackets 30 of a pedestal 3|. Pivotally mounted on said pedestal is a single acting hydraulic cylinder 32, the plunger 33 of which is adapted to engage the yoke 28. Coiled springs 34 are provided to connect the yoke 28 with the pedestal 3| so as to urge the yoke backward when the hydraulic plunger 33 is relieved from pressure. During this backward movement the yoke engages a projection 35 on the sleeve 25, so that said sleeve with the driven head 4, after disengaging the mold, occupies a position somewhat as shown in dash and dot lines in Fig. 3.

The driven head 4 of the mold is s pported in the stationary sleeve 25 through a ball bearing 36, and is provided on vits inner side with four lugs A3l each having a taper inner surface designed to engage frictionally with a corresponding conical outer surface 38 of the mold I. Instead of conical, the last said surface may also he spherical, and the same applies to the opposite end of the mold. In the interstices between the lugs 3l, the driven head 4 is provided with fins 39, which during rotation of said head and of the mold I produce a strong current of air between said elements, whereby those portions through which the heat of the mold is adapted to be transferred to the ball bearing are intensively cooled. If necessary, the cooling of the ball bearing can still be improved by ample forced lubrication thereof and by cooling of the returned oil, and if necessary also by water cooling of the sleeve 25.

The revolving parts are so arranged that they can be readily removed from the sleeve 25 and replaced by other parts, which may have different inner diameters.

Since in a machine as illustrated in Figs. 3-5 the driven head is hydraulically forced against the mold, said head may cooperate with a driving head in a fast head stock, which nee'd be adapted for axial displacement only in case molds of various lengths are to be used. If a cast flask is to be charged out of the machine and a freshly lined mold is to be inserted, the driven head is swung backward and thereafter again swung for- -ward by the outlet and the inlet of water from and into the cylinder 32.

The driving head in accordance with Fig. 6 acts as a fan or impeller since itis provided with apertures or passages with iins 40, by means of 60 which a current of air is forced into the mold in the direction indicated by the arrows. This cur-v rent of air also cools the driving head itself. Direct transference of heat from the mold I to the head 3 is minimized by the fact that the mold 35 is frictionally engaged only by a few lugs 4I of small height, so that the gaps between the head and the mold are relatively narrow and a small portion only of the air canescape through said gaps. A diaphragm 42 serves to prevent radiant 70 heat of the hot metal from heating the driving head.

In accordance with Fig. '7, the driving head is provided with passages 43 not fitted with fins and enclosed on the outside by a stationary case 44 75 sired, the compressed air or gas may be supplied through the hollow drive shaft.

In Figs. 6 and '1, the driving head is slid on a reduced end portion of the -shaft and secured thereto by means of a disc 41 with screw bolts 4B, and prevented from rotation with respect to the shaft by means of a key 46. In this manner,

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the head can easily be detached from the shaft and replaced by another one with the same or with a dierent diameter. In order that the machine may operate satisfactorily, it is necessary for the driven head to be in accurate register with the driving head. Withthis object in view, the non-revoluble sleeve of the driven head may, after ,the erection of the machine, be trued up by means of a boring bar or spindle mounted in exactly concentric relation with the driving head. Alternatively, before erecting the parts on the side of the pouring spout, an exact counterpart of the mold is secured to the driving head and suitably supported at its free end, whereupon the driven head 'with associate parts is suspended from said free end and the pedestal is eventually secured in position to the foundation.

I claim:

1. A' centrifugal casting machine for the manufacture of pipe and other cylindrical castings in refractory lined molds or iiasks, comprising a tatably supporting said driven head. a yoke rotatable about a fixed axis and supporting the .said non-rotatable part, and yieldable means tending to urge said yoke into engagement with the mold. l

driving head and a driven or casting head, a mold or ask axially clamped between said heads and supported thereby, a non-rotatable part rotatably supporting said driven head, a yoke rotatable about a fixed axis and being pivotally connected to the said non-rotatable part. and yieldable means tending to urge said yoke into engagement with the mold.

3. In a machine as claimed in claim 1. a pedestal for supportingv the shaft o f the driving head with associated driving mechanism, a bed plate upon which said pedestal is adapted to be slid axially, and mechanical means for moving `said pedestal on said bed plate and for locking it relative thereto, to adapt the machine for casting pipes of different lengths.

4. A machine as claimed in claim 1 in which at least one of said heads is provided with a plurality of projections each having a bearing surface, the mold or ask being provided with a complementary bearing surface.

5. A machine as claimed in claim 1, in which at least one of the heads is provided'with a circular series of projections each having a bearing surface and formed as a iin adapted during rotation of said head to act as a propeller, the mold or flask being provided with a bearing surface complementary to the said surfaces of the projections.

6. A machine as claimed in claim 1, in which at least one of the heads is .provided with a circular series of projections each having a bearing surface, the mold or iiask being provided with a complementary bearing surface, iin-shaped members being interposed between said projecltions to act as propellers adapted during rotation of said head to forceiiuid through the clearance between the mold and the h ead.

JEREMIAS H. LEDEBOER. 

